Two novel and simple strategies for improvement of the traditional activation method for activated carbon preparation: nano-copper catalysis and Cu(ii) doping

Abstract

The present study explores the possibilities of employing copper nanoparticles (nano-copper) as catalyst and copper(II) chloride as doping agent in the activation process to prepare activated carbons from Platanus orientalis leaves by H₃PO₄ activation. The three types of carbons by original H₃PO₄ activation, nano-copper catalytic activation and Cu(II) doping activation were identified as AC, AC-Cu, and AC-Cu(II), respectively. These carbons were characterized by thermogravimetric analyses (TGA), scanning electron microscopy (SEM), BET surface area analysis and Fourier transform infrared spectroscopy (FTIR). The effects of nano-copper and copper(II) chloride on the activation of these carbons were compared and discussed. The methylene blue adsorption capacities were also studied. Thermal analysis results illustrated that introduction of nano-copper and copper(II) chloride into the activation process accelerated the decomposition of the precursor. The surface areas of AC, AC-Cu and AC-Cu(II) were 1043.967, 822.627 and 1118.900 m² g⁻¹, respectively. All the three types of carbon exhibited relatively high pore volume compared to those activated carbons with similar surface areas. AC-Cu possessed more surface functional groups than the other two samples. The three types of carbon presented high methylene blue adsorption capacities; in particular, AC-Cu and AC-Cu(II) adsorbed more methylene blue than AC.